Midway through the round, Sonnen took Rua to the mat with a double underhook throw. After he landed several head strikes while on top of Rau, Sonnen turned Rua over with Rua's head locked under his arm, forcing Rau to tap out.

The 36-year-old Sonnen, from West Linn, Ore., lost by technical knockout in his last two fights to Anderson Silva and Jon Jones.

The 31-year-old Rua dropped two of his previous three bouts, losing by decisions to Dan Henderson and Alexander Gustafson while earning technical knockout over Brandon Vera.

The bout was the main event of the debut of the UFC Fight Night Series on Fox Sports 1.

In the co-main event, heavyweight Travis Browne of Albuquerque, N.H., knocked out Alistair Overeem of the Netherlands at 4:08 of the first round in a scheduled three-round bout.

Browne dropped Overeem with a left front kick to the face. Browne followed up with three right hands to the head before referee Mario Yamasaki stopped the fight.

Brown improved to 15-1-1. Overeem dropped to 36-13, with one no contest.

Former World Extreme Cagefighting featherweight champion Uriah Faber of Sacramento won a three-round unanimous decision against Iuri Alcantara of Brazil.

In the opening minute of the fight, Alcantara threw Faber to the mat, but after Faber reversed positions, he was in control for the rest of the fight. Faber kept Alcantara on the mat for most of the final two rounds, landing several punches to the head.

In a scheduled three-round welterweight bout, Matt Brown of Columbus, Ohio, knocked out Mike Pyle of Las Vegas at 29 seconds of the first round.

Boston's John Howard won a three-round split decision over Uriah Hall of New York at middleweight.

In the opening bout of the main card, lightweight Michael Johnson of Boca Raton, Fla., won a three-round unanimous decision over Joe Lauzon of Bridgewater, Mass.